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Chapter 1:

Humans in the World of Biology

BIO 105

What is the definition of “Life?”

2. Living things are made of cells.

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3. Living things reproduce.

• Asexual reproduction

– Common in single-cell organisms

• Sexual reproduction

– Common in multicellular organisms

4. Living things use energy and raw

materials.

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5. Living things respond to their

environment.

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Biological Classifications Taxonomic Classification of Humans

Levels of Biological Organization

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The Scientific Method

This is a multi-step process that is used to study Biology (and other disciplines as well).

1. Make careful observations, and ask

a question about the observations.

i.e.

What factors determine body weight?

How is resting heart rate different between

exercisers and non-exercisers?

1. Make careful observations, and ask

a question about the observations.

• Perform background research

• Be careful of different types of source material

• NCBI PubMed

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2. Construct a testable hypothesis to

answer your question.

A hypothesis is an educated guess about how things work.

“If ____[I do this] _____, then ____ [this] _____ will happen.”

3. Make a prediction based on your

hypothesis, and test it with a controlled experiment.

• Test only one variable at a time

• A variable is something that is changed by the researcher to see how that change effects the outcome of the study

• Control vs. experimental groups

• Dependent vs. independent variables

4. Draw a conclusion and repeat your experiments.

Is the hypothesis supported?

5. Make new predictions, and test them.

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Clinical trials

• Individuals are randomly placed in either control or experimental groups

• Control group receives placebo,

experimental group receives drug

• Double-blind studies

• Individuals must give informed consent

Epidemiological Studies

• Look at patterns in large populations to find a correlation between a variable and its suspected effects.